超高效液相色谱-串联质谱法同时测定牛乳中3 类15 种抗生素残留

建立牛乳中青霉素类、磺胺类、四环素类3 类 15 种抗生素残留量同时测定的超高效液相色谱-串联质谱检测方法。样品经乙腈-水溶液（3∶1，V/V）提取、HLB固相萃取小柱净化、氮气吹干后用1.0 mL流动相溶解残余物。采用ZORBAX Ecliplus C18色谱柱，乙腈和5 mmol/L甲酸铵溶液（含体积分数0.2%甲酸）作流动相梯度，质谱选择多反应监测正离子模式测定，外标法定量。结果表明，15 种抗生素在相应的浓度范围内线性良好，相关系数均大于0.999；在3 个不同添加水平下，平均回收率为75.1%～103.7%，相对标准偏差为1.4%～7.3%，检出限（RSN≥3）和定量限（RSN≥10）分别为0.2～4.0 μg/kg和1.0～4.0 μg/kg。方法简便快速、灵敏度高，适合15 种抗生素同时检测，为牛乳中抗生素多残留测定提供了新的方法。

Simultaneous Determination of 15 Antibiotics Residues in Milk by Liquid Chromatography Tandem Mass Spectrometry

A new approach for the simultaneous determination of residues of three classes of antibiotics, i.e., penicillins,
sulfoamides and tetracyclines, in milk by ultra performance liquid chromatographytandem mass spectrometry (UPLC-MSMS)
was established. Samples were extracted with acetonitrile-water (3:1, V/V), cleaned up using an HLB SPE cartridge and
blown to dryness under nitrogen and the residues were then dissolved in 1.0 mL of mobile phase. A total of 15 analytes were
separated on ZORBAX Ecliplus C18 column with a mobile phase composed of acetonitrile and 5 mmol/L formic ammonium
acetate solution containing 0.2% formic acid with gradient elution, detected by ESI-MS/MS and quantified by the external
standard method. The correlation coefficients of the linear calibration curves were over 0.999 in the corresponding
concentration range. The average recoveries of the 15 analytes ranged from 75.1% to 103.7%, with relative standard
deviations (RSDs) at three spiked concentrations of 1.4%–7.3%. The limit of detection (LOD, RSN≥3) and quantification
(LOQ, RSN ≥ 10) were 0.2–4.0 and 1.0–4.0 μg/kg, respectively. The new method is simple, fast, sensitive and reliable, and it
is suitable for the determination of antibiotic residues in milk.